Ultrasonic sensor unit

Abstract

The present invention relates to an ultrasonic sensor unit comprising a logic unit and an ultrasonic array unit, wherein the ultrasonic array unit is configured to emit and / or receive at least one ultrasonic wave, wherein the logic unit is configured to apply a first filter with a finite impulse response to the received ultrasonic threshold in order to generate a first filter output signal, wherein the logic unit is configured to apply a first channel-specific filter to the filter output signal in order to feed a first result of the first channel-specific filter into a matched filter.

Description

State of the art

[0001] The present invention relates to an ultrasonic sensor unit and a vehicle.

[0002] Currently, a wide variety of solutions exist for evaluating ultrasonic signals in the automotive sector. Due to the increasing number of ultrasonic sensors in vehicles, as well as the rising performance and quality requirements for these sensors, the demand for innovative and robust ultrasonic sensors is constantly growing.

[0003] The continuous reduction of weight in the vehicle sector to reduce fuel consumption, as well as increasing competition, is causing cost pressure, leading to a greater demand for cheaper and more efficient vehicle components. Disclosure of the invention

[0004] The ultrasound sensor unit according to the invention, with the features of claim 1, has the advantage over the known device that a digital filtering of a downsampled signal can be performed, wherein the digital filter has a low amplitude and a low phase shift with a constant group delay across the frequency ranges. Thus, the accuracy of the evaluation of the ultrasound signals can be significantly improved. Furthermore, preferably, the received ultrasound signals can be more easily placed in the context of the environment of the ultrasound sensor unit by means of the digital filter, by determining a sign, to deduce whether the delay is towards the ground, towards the sky, a ceiling, or the like.

[0005] According to the invention, this is achieved by the ultrasonic sensor unit comprising a logic unit and an ultrasonic array unit, wherein the ultrasonic array unit is configured to emit and / or receive at least one ultrasonic wave, wherein the logic unit is configured to apply a first filter with a similar impulse response to the received ultrasonic wave in order to generate a first filter output signal, wherein the logic unit is configured to apply a first channel-specific filter to the filter output signal in order to feed a first result of the first channel-specific filter into a matched filter.

[0006] Preferably, a first and a second transducer element can receive an ultrasonic wave. The ultrasonic waves can each be converted into a digital signal using an analog-to-digital converter. The digital signal can be downsampled, for example, from 5-8 MHz to 100-200 kHz. The downsampled signal can be filtered. Furthermore, a second downsampling from 100-200 kHz to 20-40 kHz can be performed. The twice-downsampled signal can be filtered again. A channel-specific filter can be applied to this filtered signal. The steps described are preferably performed for both the first and second transducer elements. The results of the channel-specific filters are fused and fed into a detection algorithm.

[0007] Beam steering is preferably achieved by delaying the received signals of certain transducer elements relative to other elements. For example, delaying the signals of the upper two elements relative to the lower two elements steers the received beam upwards. Delaying the signals of the left two elements relative to the right two steers the beam to the left.

[0008] Preferably, the signal delay for beam control can be applied directly before the summation of the signals and the calculation of the match filter. For example, due to the sampling frequency of only 25 kHz, a delay of a single sample would result in a time delay approximately four times greater than is typical for 90° beam control. The signal delay should preferably be adjustable in small fractions of a sample.

[0009] In this example, the channel-specific filters can be designed such that the amplitude and group delay are constant. For example, a digital filter with an order of 20 might result in a group delay of approximately 20.2578 samples. After applying the filter, the signal is preferably shifted by 20 samples, resulting in a group delay of approximately 0.2578 samples.

[0010] If the signals of the first part are filtered with this special filter and the bottom row remains unfiltered, the following delay results: 0.2578×40μs=10.312μs0.2578×40μs=10.312μs.

[0011] The same method could also be used for the second part, with a group delay of 20.3329. After compensating for the 20-sample delay, the delay between the rows is: (0.2578−0.3329)×40μs=−3.004μs(0.2578−0.3329)×40μs=−3.004μs

[0012] Negative delay can be used to change the direction of the beam control (e.g., positive delay upwards, negative delay downwards).

[0013] With this approach, the resolution of the beam control preferably depends not only on the sampling frequency but also on the complexity of the digital filter. Increasing the filter order optimizes the amplitude distortion. Angular resolutions of less than 1° are easily achievable with the ultrasonic sensor unit. By applying different filters in parallel to the same received signals in the 25 kS / s range, multiple beams for different reception directions in space can be generated simultaneously.

[0014] The dependent claims describe preferred embodiments of the invention.

[0015] Preferably, the first channel-specific filter is configured to create a signal offset for beamforming.

[0016] One advantage of this embodiment is that beamforming allows for local resolution of the ultrasound signal.

[0017] Preferably, the logic unit is configured to divide the received ultrasound wave into a first part and a second part, wherein the logic unit is configured to apply the first filter with the finite impulse response to the first part in order to generate the first filter output signal, wherein the logic unit is configured to apply a second filter with a finite impulse response to the second part in order to generate a second filter output signal.

[0018] One advantage of this design is that the respective filters with their finite impulse response can be individually adapted to the specific composition. For example, individual delays can be adjusted accordingly.

[0019] Furthermore, the logic unit is preferably configured to apply a second channel-specific filter to the second filter output signal in order to feed a second result of the second channel-specific filter into the adapted filters.

[0020] One advantage of this embodiment is that the first channel-specific filter and the second channel-specific filter can be matched in such a way that the amplitude response and the group delay of the frequencies are constant. This significantly simplifies the evaluation of the ultrasound signals.

[0021] Furthermore, the logic unit is preferably configured to maintain a constant amplitude response and group delay of the frequency of the first channel-specific filter and / or the second channel-specific filter.

[0022] One advantage of this embodiment is that, with such a design, a difference between a first filter output signal and a second filter output signal can be used to achieve or adjust a negative delay in the direction of the beam steering, thus increasing the accuracy of the evaluation of the ultrasound signals.

[0023] Preferably, the logic unit is configured to apply at least a sine function and / or a DEC4 function to the first part and / or the second part in order to form an input signal for the first finite impulse response filter and / or for the second finite impulse response filter.

[0024] One advantage of this embodiment is that the cosine function, the sine function and / or DEC4 function can be adapted depending on the desired delay between the first channel-specific filter and the second channel-specific filter.

[0025] Preferably, the logic unit is configured to apply at least one analog-to-digital converter or an IQ modulator to the received signal in order to form the first part and / or the second part.

[0026] One advantage of this embodiment is that the processing of the signals at the ultrasound array unit can be simplified.

[0027] Preferably, the logic unit is configured to adjust the first channel-specific filter and / or the second channel-specific filter so that any delay between an evaluation of the first part and an evaluation of the second part results in a sign change.

[0028] One advantage of this embodiment is that by determining a sign or similar, the ultrasound signals can be placed in a spatial context.

[0029] Preferably, the logic unit is configured to set a resolution of a scanning angle of the ultrasonic sensor unit by adjusting a sampling rate and / or an order of the first channel-specific filter and / or the second channel-specific filter.

[0030] One advantage of this embodiment is that the resolution can be set according to the application; for example, a low resolution may be required in a given situation, such as when there are larger distances between the ultrasonic sensor unit and the object, and this can be adjusted accordingly.

[0031] Another aspect of the invention relates to a vehicle which has an ultrasonic sensor unit as described above and below. Brief description of the drawings

[0032] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawing shows: Fig. 1 an ultrasonic sensor unit according to one embodiment, Fig. 2 a block diagram to illustrate the operation of an ultrasonic sensor unit according to one embodiment, Fig. 3 a diagram illustrating the operation of an ultrasonic sensor unit according to an embodiment Fig. 4 a vehicle according to an embodiment, and Fig. 5 A block diagram illustrating the operation of an ultrasonic sensor unit according to one embodiment. Embodiments of the invention

[0033] Preferably, all identical elements, units and / or steps in all figures are labelled with the same reference symbols.

[0034] Fig. Figure 1 shows an ultrasonic sensor unit 10 according to one embodiment. The ultrasonic sensor unit 10 comprises a logic unit 12 and an ultrasonic array unit 14, wherein the ultrasonic array unit 14 is configured to emit and / or receive at least one ultrasonic wave, wherein the logic unit 12 is configured to apply a first filter with a similar impulse response to the received ultrasonic wave in order to generate a first filter output signal, and wherein the logic unit 12 is configured to apply a first channel-specific filter to the filter output signal in order to feed a first result of the first channel-specific filter into a matched filter.

[0035] Fig. Figure 2 shows a block diagram 200 illustrating the operation of the ultrasonic sensor unit 10 according to one embodiment. In block 202, the ultrasonic signals are received by the transducers. A first channel 200a and a second channel 200b are shown as examples. In blocks 204, the received ultrasonic signals are converted by the transducers using an analog-to-digital converter. In the respective block 206, the frequency is changed from 6.4 MHz to 200 kHz, based on the output values ​​of the analog-to-digital converter. In step 207, the outputs of the respective block 206 are divided into a first group 208 and a second group 210 for further evaluation.

[0036] In the first group 208, there is a first block 212 that processes the signal using a cosine function over 50 kHz, into which the signals from block 206, or a first part thereof, are fed. In the subsequent block 216, a DEC4 function is applied to the results of the cosine function 212. In step 220, a first filter with a finite impulse response can be applied to the results of the DEC4 function in block 216. Based on the output of the first filter with a finite impulse response 202, a channel-specific filter 224, 226 can be applied. The channel-specific filter 224, 226 is specific to the respective channel 200a, 200b. In the example shown with two channels 200a, 200b, there is therefore a first channel-specific filter 224 and a second channel-specific filter 226.

[0037] In the respective second group 210, an output signal 206 is fed into a sine wave block 214 at 50 kHz. The results of the sine wave block 214 are processed in block 218 using a DEC4 function. The second finite impulse response filter 222 processes the results of block 218. The results of the second finite impulse response filter can be processed by the first channel-specific filter 224 or the second channel-specific filter 226, which is specific to the respective channel.

[0038] The respective outputs of the first channel-specific filters 224 are fused with the respective outputs of the second channel-specific filters 226. To do this, the result of the first channel-specific filter 224 of the first group 208 of the first channel 200a is fused with the result of the second channel-specific filter 226 of the first group 208 of the second channel 200b in a first fusion 228a. This thus concerns the branch with the cosine function. The result of the first channel-specific filter 224 of the second group 210 of the first channel 200a is fused with the result of the second channel-specific filter 226 of the second group 210 of the second channel 200b in a second fusion 228b. This thus concerns the branch with the sine function. The results of these fusions are fed into a modified block 230. Preferably, the MF calculation can be performed in block 230, in particular based on the fusion 228.

[0039] Fig. Figure 3 shows a diagram 300 illustrating the operation of the ultrasonic sensor unit 10 according to one embodiment. The diagram 300 has a first axis 302, which represents a group delay in samples. More preferably, the diagram 300 has a second axis 304, which represents the frequency. Furthermore, a result 306 is plotted in the diagram, which can be the result of an exemplary digital filter of the ultrasonic sensor unit 10.

[0040] Fig. Figure 4 shows a vehicle 100 according to one embodiment. The vehicle 100 preferably has an ultrasonic sensor unit 10, as described above and below.

[0041] Fig. Figure 5 shows a block diagram 300 to illustrate the operation of the ultrasonic sensor unit 10 according to one embodiment. As shown in the Fig.As shown in Figure 5, the ultrasonic sensor unit 10 can have at least two transducer elements 302, 320, each forming a channel. Various measures can be taken along the channel. Preferably, an analog-to-digital converter 304, 322 can convert the signal from the transducer elements 302, 320 into digital signals. The ultrasonic sensor unit 10 can process the digital signals by means of a first downsampling stage 306, 324, in particular from 5 to 8 MHz to 200 to 400 kHz. The signal after the first downsampling stage 306, 324 can be fed into a first filter 308, 326. The results of the first filter 308, 326 can be fed into a second downsampling stage 310, 328. The results of the second downsampling stage 310, 328 can preferably be directed into a second filter 312, 330. Channel-specific filters 314 and 330 are applied to each channel based on these results.The results of the channel-specific filters 314, 330 are fused in step 316 and fed into a detection algorithm 318.

Claims

[1] Ultrasonic sensor unit (10) comprising a logic unit (12) and an ultrasonic array unit (14), wherein the ultrasonic array unit (14) is configured to emit and / or receive at least one ultrasonic wave, wherein the logic unit (12) is configured to apply a first filter with a finite impulse response to the received ultrasonic wave in order to generate a first filter output signal, wherein the logic unit (12) is configured to apply a first channel-specific filter to the filter output signal in order to feed a first result of the first channel-specific filter into a matched filter. [2] Ultrasonic sensor unit (10) according to claim 1, wherein the first channel-specific filter is configured to form a signal offset for beamforming. [3] Ultrasonic sensor unit (10) according to one of the preceding claims, wherein the logic unit (12) is configured to divide the received ultrasonic wave into a first part and a second part, wherein the logic unit (12) is configured to apply the first filter with the finite impulse response to the first part in order to generate the first filter output signal, wherein the logic unit (12) is configured to apply a second filter with a finite impulse response to the second part in order to generate a second filter output signal. [4] Ultrasonic sensor unit (10) according to claim 3, wherein the logic unit (12) is configured to apply a second channel-specific filter to the second filter signal in order to feed a second result of the second channel-specific filter into the adapted filter. [5] Ultrasonic sensor unit (10) according to one of claims 3 to 4, wherein the logic unit (12) is configured to keep the amplitude response and group delay of the frequencies of the first channel-specific filter and / or the second channel-specific filter constant. [6] Ultrasonic sensor unit (10) according to one of claims 3 to 5, wherein the logic unit (12) is configured to apply at least one cosine function, one sine function and / or one DEC4 function to the first part and / or the second part in order to form an input signal for the first filter with the finite impulse response and / or for the second filter with the finite impulse response. [7] Ultrasonic sensor unit (10) according to any one of claims 3 to 6, wherein the logic unit (12) is configured to apply at least one analog-to-digital converter and / or one IQ modulator to the received signal in order to form the first part and the second part. [8] Ultrasonic sensor unit (10) according to one of claims 3 to 7, wherein the logic unit (12) is configured to adapt the first channel-specific filter and / or the second channel-specific filter such that a delay between an evaluation of the first part and an evaluation of the second part has a sign change. [9] Ultrasonic sensor unit (10) according to claim 8, wherein the logic unit (12) is configured to set a resolution of a scanning angle of the ultrasonic sensor unit (10) by adjusting a sampling rate and / or an order of the first channel-specific filter and / or the second channel-specific filter. [10] Vehicle (100) comprising an ultrasonic sensor unit (10) according to one of the preceding claims.

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